lndpm seems to only work if all HDF and Landsat files are in the same directory. about ledaps HOT 3 CLOSED

Correct.  The applications in LEDAPS expect that the user changes directory to 
the location of the input LPGS files and associated LEDAPS files.  The 
do_ledaps.py script handles the chdir to the directory of the LPGS data and 
then returns to the current directory when completed.

Regarding the ancillary data, LEDAPS expects the data to be in a format and 
directory structure similar to that in the .tar.gz file provided.  The 
updatencep.py and updatetoms.py scripts in the ledapsAncSrc directory will 
allow you to update these base ancillary files.  Use the --help command-line 
argument to run those scripts based on your own needs.

http://landsat.usgs.gov/espa/files/ledaps_anc_1980-2012.tar.gz

You can download this file and use it as your initial set of ancillary data.  
The source code and scripts in ledapsAncSrc will update these files if you run 
them on a nightly or quarterly basis.

How to convert MTL.txt to hdf format in Envi 4.7... Plz help

send mail at :-
[email protected]

It's unclear to me why you would want to convert the MTL.txt file to HDF for 
ENVI.  The MTL.txt file is a metadata file.